RESPONSE AND PERFORMANCE OF TEST PAVEMENT TO ONE FREEZE-THAW CYCLE

Two full-scale test pavements (RTM1 and RTM2) and one rehabilitated, overlaid variant of the second test pavement (RTM3) have been tested in the Danish Road Testing Machine. These test pavements were instrumented to enable measurements of the strains and stresses in the pavement layers, and the resilient and permanent strains in the subgrade at specific loading repetitions. This report describes the RTM3 freeze-thaw study conducted during 1999. The temperatures and soil suctions in the pavement layers were measured during the freeze-thaw period. The development of pavement response and pavement performance under a constant 60 kN dual wheel load was very closely monitored during the early, critical stages of the thawing period. As a result of the RTM3 freeze-thaw study, a new subgrade permanent strain model has been developed from the research data from the RTM1, RTM2 and RTM3 test pavements, which were constructed, instrumented and load tested in the Danish Road Testing Machine between 1995 and 1999. The new model predicts the permanent strains in the subgrade. The coefficients and powers in the new stress-strain model were derived using measured data from the first two test pavement structures.